Autocom has been very popular with the group, but they are not cheap. It does allow you to connect to a radio for group bike-to-bike communications. Intaride have also been used by several members.
If you can get one with noise cancelling, it makes the experience that much better.
It really depends on what you want it for. If just chatting to one other person then bluetooth headsets appear to be a good option, though they can have distance issues. If wanting to talk to a group, then something that links to a radio would be best. If you are going down the radio route, we tend to use the Kenwood PMR radios (analogue 3301/3501 ProTalk or digital 3401 Protalk) The digital radios also allow you to use the analogue setting so can still talk to those with older radios.
Hope this helps
I have been wrestling with comms as well, with the added complication of needing to integrate the BMW TFT and Nav 6 into the equation.
Setting the BMW stuff aside (its complicated!) I have settled on a Sena SU10 headset with two bluetooth channels. The first channel pairs to the bike giving satnav, music and phone. The second channel I use for bike to bike using a Sena SR10 plugged into a Kenwood radio. The Sena SR10 has a separate push to talk button that you pop into one of the grips. I also have an external aerial that plugs into the radio. The Kenwood radio is a 4 watt version that has been tuned to operate on the public network so theoretically gives better range? The radio and the SR10 sit in a bar bag where It could if required be powered from the assessory socket. This system works well but I have yet to test the radio range in the context of a moving group but will report as soon as I have.